Japanese Kaiten Torpedo

IJN Navy officers in 1944, were the designers, Lts Hiroshi Kuroki and Sekio Nishina. The pair were killed while testing the weapons.

In the desperate final year of WWII in the Pacific, very few people on both sides knew of the existence of the Japanese kaiten human torpedo. It was a top secret weapon developed by two “Circle 6 metal fitting” and only a few in the Imperial Navy knew what it really was.

The kaiten was the underwater equivalent of the Kamikaze suicide plane. Although the human torpedo pilots did not die in a blaze of glory as their air force counterparts, they all believed in their cause and there was no shortage of volunteers for the top secret program.

The kaiten was powered by a Type 93 “Long Lance” torpedo engine fitted to a long tubular body. The engine was oxygen-powered and had a maximum speed of 30 knots (34.5 mph). The 54-foot weapon packed a 1550 kg (3,420 pound) warhead and was controlled and guided by a human operator. There was a tiny pilot’s compartment which had a periscope and a gyro-compass to guide him to the target. Once launched, the weapon could not be recovered. There was a self-destruct button if the pilot failed to hit his target.

Kaiten Type-10 schematic

To sink a submarine was very difficult. The killing radius of the exploding depth charge, depending on various circumstances such as depth, payload, and strength of the target’s hull, was around 10 to 13 feet. From 26 to 33 feet, serious damage could be inflicted. It took a lucky hit to sink a submarine; most were sunk after being battered continuously until they lost power or air. The US Navy had perfected anti-submarine warfare using high tech equipment and teams of destroyers and destroyer escorts. The danger point for the submariners was about 12 hours without fresh air. By forcing the sub to surface or preventing it from surfacing for air, its destruction was assured.

Petty Officer Yutaka Yokota, a kaiten pilot on the I-36, recalled: “Then came the depth charges. They felt like a giant pile driver smashing into the side of the I-36. She shook and swerved, throwing me to my knees. The wardroom sofa leaped fully two feet above the deck and toppled over on its side. Every light that I could see went out, and only about half of them came on again.”

USS Sproston

The I-36 was taking a severe beating and there was nothing she could do. It had launched one kaiten, but it still had 5 more strapped to the deck. Sugamasa wanted to dive down to 325 feet, but his cargo prevented him from doing so. To dive deeper meant that he would destroy the kaitens due to heavy underwater pressure.
Oil and debris came bubbling to the surface, but Cdr. Esslinger on the USS Sproston wasn’t falling for that old submariner’s trick. The crew smelled blood in the water and increased their resolve. They had knocked down several Japanese planes, but wanted to add a submarine to their tally.

LCdr. Sugamasa was running out of options. Then Ensign Minoru Kuge rushed into the con and volunteered to man his kaiten and counter attack. All of the electric rudders on the small crafts were damaged, but they could be steered manually. Petty Officer Hidemasa Yanagiya also insisted to sortie. Sugamasa knew that a counter-attack had little chance of success. These two brave men were going to sacrifice themselves to lure the destroyer away from their submarine so that she could escape.

Yokota’s kaiten was badly damaged. He had sortied twice before, only to be thwarted by mechanical failures in the temperamental kaiten. He was confident that the third sortie would be the charm. Now a bystander, he stood by clutching a vial of cyanide and thought “Once they made their direct hit and water came rushing into our hull, I was going to swallow the container’s contents. I could not bear to think of death by drowning or suffocation.”

Kuge and Yanagiya quickly boarded their kaiten through a tight hatch and were sealed shut. The engines started, the clamps were released, and the two kaitens whirled their way toward the surface. The skipper and his sonarmen listened intently through their earphones. Fifteen minutes later, the first contact was made.Sproston had spotted a kaiten and made a run towards it. The conning tower and periscope were clearly visible at quite a distance.Then the 5-inch guns opened up. Sugamasa and his sonarmen heard faint explosions. “We made a direct hit!” recalled Roberts. “I saw the small black conning tower go sailing off into the air!” There was wild jubilation! The Sproston had scored.

Down below in the I-36, they later heard a gigantic boom; a kaiten had exploded. But which one, Kuge or Yanagiya? Believing that it had scored a kill, they cheered. But they were wrong. The depth charges kept coming. From noon until night, the destroyer pounded the submarine until their inventory of depth charges was depleted. Finally, the destroyer retired from the scene. The I-36 limped back into port like a beaten dog on 6 July 1945. For Yutaka Yokota, he was unsuccessfully lucky, for he lived to tell about it.

Through the diligent efforts of Don Roberts (Jim’s son), the connection between the Sproston and the I-36 was made. Don located Yutaka Yokota in Tokyo and exchanged letters. The USS Sproston Association invited the former kaiten pilot to their reunion in Orlando, Florida in September 1990. Yokota could not attend due to ill health. The old sailors were looking forward to meeting Yokota at the 1992 reunion in Chicago, but were saddened to learn that he had passed away on 16 March 1991 of cancer at age 65.

Jim Roberts had sent a letter to Yokota prior to his passing. In his letter, Jim wrote: “We tried our best to sink you. But I am glad that we did not do so.” This letter was read at Yokota’s funeral wake. About a hundred of Yokota’s comrades, many of them from the kaiten program and the submarine service, attended his funeral. “I wish we could have met,” sighed Jim. “We had so much to talk about.”
Jim Roberts passed away at his home in Lakewood, CA in 2004.

Rate this:

Share this:

Like this:

LikeLoading...

Related

About GP Cox

Everett Smith served with the Headquarters Company, 187th Regiment, 11th A/B Division during WWII. This site is in tribute to my father, "Smitty."
GPCox is a member of the 11th Airborne Association. Member # 4511 and extremely proud of that fact!

I haven’t been studying much about Europe, Africa and the Middle East as I should. I intend to read more when this blog is finished. That’s an interesting piece of info and something I’ll have to remember to read up on. Thanks, Beari.

Standing in front of the Kaiten makes you realize just what a deathtrap it was . . . well, it would eventually be a deathtrap if successfully deployed but it stood a good chance of being a deathtrap before successfully completing the mission.

One other thing which struck me about the above account is that the Kaiten pilot would prefer to die from a cyanide vial rather than drowning. I suppose it’s a personal choice, but cyanide is not an instantaneous death and can take from one to four minutes to kill. You lose consciousness pretty quickly from the intense pain but death is not assured (depends on the dose).

Not sure why a gun wouldn’t have been considered a faster and more certain way to commit suicide. Guns might not have been issued in a submarine, but I’m also not sure why they would have the cyanide vial to begin with. I’d have thought it wouldn’t be standard issue. There’s an interesting Wikipedia article on Suicide pills.

He makes a good point about cost of production, but would we need quite so many? Wouldn’t it be to Japan’s advantage to have a number of them in their own fleet and any other nation in that area that wants to remain independent? Once again I complain about us being the sole fighter against tyranny.

Wow, setting aside the fact that this is about war, death, and suicide, what an exciting rock ’em, sock ’em tale! I remember reading in a novel, based on real events I think, about a similar German effort, from the Channel Islands I think, to attack the Allied ships in the Channel, and at the Normandy beachhead.
I’ve walked through subs from WWII, both American and German, and they were pretty darn claustrophobic with the hatches all open and fans going!

It was. I was just trying to give others a reference to how long Japan had midget subs. I have done a couple of posts about the attacks on Australia, but still there are people who are unaware of the Japan attacks on your nation.
There were very few parts of this world NOT affected by that war.

It always amazes me that a country can convince men to go on suicide missions. I was surprised that there were so many of the men at the funeral as would not have thought there would have been that many survivors. Maybe they were just the organizers!

I know someone who spent years as a submariner in our navy. I’m anxious to ask him about the kaiten, to see if he knows about them. I suspect he does. I’m fascinated by all forms of underwater warfare, just because I know I couldn’t do it. I don’t think they want a claustrophobic submariner!

When fanatics take over a whole culture and country, insanity becomes a norm. There’s no limit of examples in World History.
It’s insane enough to murder other people, but yourself also? I see no honor where people are not capable of thinking independently and rationally.

I think the common bond of having served in a navy is probably stronger than the hatred that was thrust upon these men. That duty set aside, I believe they could be friends. I wish we could come to that conclusion first.

Can or should we say the terrorists of today are something like the Kamikaze in the past? Noboday wants to hear something about a war this days, but what else is it? The officials of Gaddhafi and Sadam Hussain lost their wellfare. Now they are try to get back their goods.
Best wishes! Michael

Oh, we are definitely in a war. We just don’t call it that officially because then Congress has to approve it. I’m afraid the suicide bombers of today are just as desperate (or being used by desperate men) to try and further their agenda, I agree.
Thank you for commenting, Michael!

I learned something new again. I don’t remember reading about the kaiten program. Most of the kamikaze attacks I read were made by fighter pilots. I can’t see myself inviting the enemies even after all those years. The current generation is something else. They have nothing to do with what the Japanese militarist of WWII did. I can be friends with the current generation. As a matter of fact, one of my best friends is Japanese. Love the cartoon. Great post GP.

Sad that they didn’t get to meet up in the end. I’ve seen a few documentaries where old soldiers meet their counterparts from the ‘other side’ and it is heartwarming to see there is no rancour between them. I think maybe the fact that they went through the same most awful stuff makes for a bond that us on the outside couldn’t understand.